What's Left Of Us
by BrownBlossoms
Summary: When benders discover how to transform themselves into monstrous cannibals called Titans, the Fire Lord is forced to call upon old friends to put an end to the bloodshed. But can he protect those he loves from this new threat, and can he deal with loving someone amid the mounting chaos? An ATLA/Attack on Titan, Zutara crossover fic.


**Author's Note: **Hello everyone! This is going to be a multi-chapter ATLA/Shingeki no Kyojin (Attack on Titan) crossover fic that places Titans in the world of Avatar. You don't need to know anything about AoT because I'm not really using many canon elements from the manga (besides the Titans, haha). Not sure exactly how long this will be, but it's been fun to write so far. So, I hope you have fun reading! :)

Disclaimer: I don't own these fantastic characters or stories, and I'm not making a dime off of this.

Thanks to my fantastic beta **MyHeartBurns4You **for proofing and offering fantastic ideas! You the best!

* * *

**Prologue: Mistakes**

_I should never have come here._

This was her last thought. Like a tendril of smoke, it curled about her - intangible, fleeting, and mournful. Wind rushed beneath her dangling feet and dread settled deep within the marrow of her soul.

She was going to die.

_NO!_

His voice rang clear, loud; the distinct sound of metal slipping from sheath followed his gravelly shout. _His dao swords_, she thought resolutely, clinging to some shred of hope. But what could he do from all the way down there, when she was so far from them all? What could any of them possibly do without Aang?

She felt an all encompassing anguish overtake her. With it, the taste of bile and the stench of rotting flesh overwhelmed her. It stared at her, then. Really stared. With a slow tilt of its head, that gaping smile expelled a foul, hot breath that coated her face. It was all bloodstained teeth, saliva coated tongue, and an unwavering smile. It gripped her tightly between rough fingers.

_Aang…_

He was gone, and there'd been nothing that they could do to stop it.

* * *

When Katara descended from the loaded passenger barge, the distinct sounds of the Fire Nation's busiest port settled within her bones. She wrung out the sea from her hair and stretched her limbs lazily against the setting sun.

_After all these years_, she pondered. _I'm back._

It'd been six, precisely. But everything still felt so familiar, so intimate.

The port was loud and turbulent, full of the midday rush. Merchants ran to and fro, carrying wares in their calloused hands. Stout young men pulled boats into the swollen shore, shouting orders and calling signals that got lost in the ocean's continual break upon the beach. Worn, faded flags whipped against the incoming sea breeze, and the pier was dotted with vendors that brandished spicy, roasted fish to entice hungry travelers tired of the bland sea fare. She closed her eyes, inhaled, and smiled.

It felt like..._home._

"Ah-ha! What a pretty Watertribe maiden." A wizened seller appeared at her side. "You must be hot in all those furs and layers you brought. Come, come - persuse my wares! I sell nothing but the finest silks in the Fire Nation."

He pointed toward his stand, but Katara noticed another, more prominent figure approaching in the distance. A tall, graceful woman fixed her gaze upon them; her thick, raven hair and sharp cut bangs veiled her taut expression. Despite the heat, she still wore the long, fingerless black gloves that had become her trademark.

Mai.

"If you waste your money on these wares, Zuko will have arranged all your Fire Nation garments to be delivered for nothing."

Katara bowed gracefully to Mai, who returned her gesture with a curt nod.

"Thanks for coming!" Katara erred on the side of politeness, but she was somewhat surprised. Since when did Katara, master waterbender and "all around hard ass" (as her pupils referred to her), need an escort? "It's kind of nice being back. Feels almost like a mini-vacation!"

Mai moved briskly, quickly outpacing the Watertribe woman who craned her neck to take in the swollen port.

"I was in the middle of a vacation, and then I was summoned to come and escort you. Funny how that works."

Katara rolled her eyes. _They_ had _to send Mai._

She sidestepped the awkward silence. "Are my brother and Suki at the palace? Or, maybe Toph?"

Katara thought back to the cryptic messenger hawk she'd received from Sokka:

_Got a weird letter from Zuko the other day. He "requests our presence" immediately, so Sukki and I are putting wedding plans on hold for whatever urgent matter this is. He better have a good excuse. And good food. You know, to make up for it. You'll probably get yours any day, so I guess we'll see you soon._

The letter she'd received was all elegant scrawls and noble insignias, but nothing concrete about exactly_ why_ they were being summoned. Katara spent the watery trek sullenly pondering it, and wondered if leaving her waterbending pupils behind was a mistake.

"Save your questions for Zuko," Mai intoned.

Together, they wove through swollen crowds that hung heavy with desperation. Katara held fast to her waterskins and struggled to stay upright against the human-shaped tide. _Has it always been this rowdy at the ports?_

Somewhere, screams broke through the ocean's calm lull; Katara stopped abruptly.

"What was that?"

A swell of bodies pressed together jaggedly near one barge; Katara could only make out flashes of fists and teeth and skin clashing amid the commotion.

"Those people," she whispered. "Mai, those people-"

"Get in." Mai motioned to a waiting palanquin before entering it herself.

Katara frowned. Even if Mai wasn't Fire Lady yet (actually, she had no clue whether or not she was), she had a duty to stop the brawl, right?

Crowds pressed against the hull as the barge attempted to push off; some even tried propelling themselves onto the deck with streams of fire. Beneath it all, a woman, delirious with something Katara couldn't name, sunk her teeth into a man who'd only begun to summon his flames. Blood poured from his wound, swelled around her mouth, and stained the dusty crimson of her garb. But he still fought and struggled to reach the ship's deck, even with her attached.

"What-what's going on?" Katara whispered hoarsely.

"Like I said: save your questions for Zuko and get. In." Mai held open the curtain for her, and pulled the woman when she wouldn't budge on her own.

* * *

The swaying, rocking motion of the palanquin churned Katara's stomach. She gripped one of the ornately cushioned seats and tried to think about anything but retching all over the decorative interior.

"How could you just...what _was_ that? And why didn't you stop it?" Katara's gaze was hard, her voice ripe with disgust. "Those are your people, and if you're going to be leading this place soon, then-"

Mai chuckled humorlessly. "They really haven't told you anything."

"Yeah, _clearly_. Care to contribute anything useful to the conversation?"

Mai sighed deeply, but offered no response.

"Does my being summoned have anything to do with what happened back there?"

"Yes. And no."

"Way to help," Katara huffed.

In six years, Mai hadn't changed much at all. She was still the lithe, drab woman that Katara had fought so fiercely against when trying to protect Aang. But her honey eyes - those now swam with a stark change that Katara was only just beginning to notice. When she cast her gaze toward the Waterbender, they held a palatable dread that seeped and curled around the space separating them. Intense, and intimate, they communicated an unspoken plea, all traces of the petty fighting that marred their youth, gone:

_I hope you can help more than I could._

For a while, silence salved Katara's anger; she was lulled to sleep by the swaying motion of the palanquin while Mai busied herself with various political scrolls. But when a violent jolt forced Katara awake quickly, it was because the unsteady palanquin had begun to tilt dangerously.

"Hold on!" Mai's strained voice reached her; she disappeared through the separating curtain as the palanquin teetered shakily.

Katara clung to the cushion beneath her and took in her surroundings. The palanquin was almost completely on its side, forcing her to slide toward the fluttering curtains at her left. Shouts and cries sounded from all directions, and Katara swore she heard the sound of komodo dragons rearing shrilly nearby.

_What the hell is happening?_

But the thick _thud_ of something massive threw her from the palanquin. She hit rough gravel and crumpled weakly against jagged rocks lining the road.

"Mai, " she called hoarsely. Her elbows scratched over the grainy surface as she tried to sit upright.

But the pounding of something new reached her before anything else did -

A large kimodo dragon was rearing and trampling over the palanquin, trying to get away from _something_. It backed toward her, it's large hooves coming dangerously close to her feet.

Katara tucked her legs, avoided one massive blow, and rolled from beneath the creature. But something else thudded to her left-one was charging through the market square maddeningly, heading right for them.

"Crap." She stood shakily, ignored the throbbing in her head, and uncorked her waterskins. "Everyone, back away!"

Frenzy gripped the square, and the din of the market was almost deafening. Those running in the opposite direction flung cries and shouts from their lips as they leapt over fallen carts and weaved around Katara's solitary form. With two sweeping moves, katara conjured icy weapons that sliced the oncoming animal behind its legs. It moaned desperately before crumpling in front of her.

"I'm sorry-I'm so sorry!" She rushed to the animal's side and attempted to calm it down. She couldn't risk any healing methods if it might still endanger others.

"Are you alright?"

A warm hand touched her shoulder, blue with the markings of tattoo she'd long since memorized.

"Aang," she breathed.

He knelt beside her and stroked the creature reassuringly. "Mai's going to help clear the square. Let me get you back to the palace; it's not safe here."

"No freaking kidding!" Katara shoved her finger into his chest. "Aang, you need to tell me _everything. Right. Now._"

"Not here," he whispered, strained. "I promise, Katara, we'll talk about it later. But right now-"

Her breath caught.

He was covered in blood. Slick with it. Encased by it. It was on his eyelashes and under his nails. It was in the ruddy color of his robes, which had turned a dank, murky brown. It was in the painful, pleading stare he gave her.

_Not his. Please, La, not his._

Elevated voices reached her ears then -

"_How could you come this way?_"

"I wasn't the one pulling it, Zuko."

"I told you - take designated safe roads. And for A_gni's_ sake, why didn't you take any guards?"

Dazed, Katara wove her fingers through Aang's robes. Bits and pieces were torn, but his warm skin was unscathed beneath them.

"I have a better question: when are you going to get a handle on this?" Mai's voice was smooth, contained.

Katara began moving toward the sound of the argument then, but Aang's fingers caught her robes.

"Sokka and Suki are holding off on lunch until you get back, and Toph's probably bored out of her mind. Seriously, we should probably be getting back." He chuckled, but something about it was off.

Something was off about everything.

Zuko's voice came in the form of a ragged plea. "Just _get her out of here _before she sees this. Please."

Mai raised an eyebrow, having noticed Katara's appearance behind the Fire Lord. Her calculating gaze connected with Katara's confused glare.

"Too late."

The Fire Lord spun on his heel, and his scarred eye widened upon seeing her.

But Katara looked past him with careful eyes and followed the small drops of blood that'd were smudged beneath his boots. Thicker, darker puddles stained the alleyway ahead.

She followed those splotches to bits and pieces of mangled flesh, to bodies ripped open and shorn apart. To persons missing halves, with entrails snaking gruesomely through the dirt. To an entirely collapsed building with pieces of ripped clothing rippling in what shards still stood.

She looked past him, fell to her knees, and wretched onto the floor.

* * *

When the palanquin finally came to a steady stop, she tore from it.

"Katara, wait-"

She ignored Aang's outstretched hand, headed instead for the Fire Lord's Kimodo Rhino. Instead of his traditional, ornate robes, he wore a crimson cloak over black and gold plated armor. Metallic designs swirled in various patterns on his collar and robes, mimicking Fire Nation insignia. When he swung one pointed boot off his stead, his long, raven hair draped to cover the dao swords at his back.

"Zuko, we need to talk about what happened back there."

She grabbed his billowing robes, forcing him to turn sharply.

"Another time," he whispered, turning from her. His voice was laced with the same malice that colored his youth, with the same palatable, metallic anger that she thought he'd left behind at the war's end.

Was he really that person again?

"You called me here for something. And...and I-I can't help you if you don't tell me what's going on."

She waited for his response. She waited with too many words on her tongue, with a too-fast heartbeat, with her fists clenched and her jaw tight.

"I haven't told the others yet."

"Have they seen what I just saw?"

Silence. More silence. He took one, hesitant step from her, then stopped. Smoke filtered from his nostrils and floated to her on the wind.

"I didn't mean for-you weren't supposed to see that. That's not what I wanted."

"We don't always get what we want." Her voice was hard with remembered hurts. "But I'm asking you as a friend to...to work _with_ me on what's happened." She closed the distance separating them. Her clammy fingers skimmed his fists, eliciting a shaky tremble from his throat.

_If I can just reach him. If I can just…_

They stood there like that for some time - his back to her front, her words burrowing into the emptiness within him. They stood there - the Waterbender and the Firebender - between a chasm that she attempted to bridge with something innate. With something that'd always fluttered beneath the surface of their friendship. They stood there, with him scowling against a hot shame that threatened to drown him in its embrace, until he let out a deep sigh.

"I didn't summon you here." He turned toward her then. "Ask your precious Avatar to fill you in."

It stung like a slap. It left a growing welt on her soul. The_ click click_ of his armor as he walked away from her punctured the thick silence in a shaky staccato. Katara bit back tears.

Gory images flittered through her mind with each sound. _Click_ - a child with entrails snaking from their mouth. _Click_ - a woman ripped limb from limb. _Click_ - heads bloodied like the pulpy residue found in fire mangos. Katara cursed lowly; she wiped a stray tear from her warm cheek.

_You don't get to walk away from me._

She took a beat. Then another breath. Then lowered herself fluidly, spidery fingers poised delicately in the air.

There may not have been a full moon lending her power, but she was still _Katara_. She was still the woman who single-handedly brought down Azula. The same woman who faced Hama under humid skies.

He didn't get to just walk away from her.

A warm, molten feeling curled its way up her spine. She felt his blood beneath the surface, felt it flowing with life. _Pluck_. Her fingers tightened, pulled, and suddenly the Fire Lord had stopped mid stride.

His breath came out in a muffled groan.

"Katara, _no_!" Aang moved toward her.

Like lightning, she slid her fingers toward her body; the Fire Lord powerlessly followed that movement, his boots skidding backward across the gravel. She stopped him inches from her, and spun him slowly.

"Tell me what that was back there."

Her voice was even, calculated. It didn't betray the growing pain that gathered in her lower back, or the pounding that'd appeared behind her eyes.

Though the Fire Lord didn't struggle against her ministrations, she noticed his trembling hands, the firmness of his set jaw, and the defiance in his eyes. No...was it defiance, or was it something more painful? His gaze was so piercing, and so thick, that it enveloped her. It begged her to decode him, to unravel and understand without words.

It said that he _had no words_ for what that was. Not yet, anyway.

Then, so quickly that she didn't have time to stop him, one of his calloused fingers traced her taut ones. How had he broken free? She felt sweat pooling below her neck. She tightened her hold over him, and forced his hand back in place.

Zuko's heavy grimace gave way to an anguished pain that danced across his being. His face had always been sharp angles and shaggy hair, but this man was someone new altogether. He walked with a gait that bore years of leadership. He spoke with the kind of raspy command that'd only appeared dimly in their youth. But he broke underneath her, then, and she saw him.

She saw the Zuko from Ozai's war, and she watched a strained tear make a trail from his eyes to his lips.

"It was my fear, and my failure, for the entire Nation to see," he rasped.

His molten eyes swam with untold truths and half lies. With the kind of fear that curls within a shelf on your soul, right next to your heart. His eyes asked her to do something, anything.

To help.


End file.
